PART II. 



CHAPTER VII. 

 SUB-KINGDOM L PROTOZOA. 



SUB - KINGDOM I. PROTOZOA. Animal simple or composite, 

 generally of very minute size, composed of a strtictureless, jelly-like, 

 albuminoid substance (termed " sareodc"\ showing no compositio?i 

 out of definite parts or segments, having no definite body -cavity, 

 presenting no traces of a nervotts system, and having either no ali- 

 mentary apparatus, or but a very rudimetitary one. 



TABLE OF THE DIVISIONS OF THE PROTOZOA. 



CLASS A. GREGARINID^. Parasitic Protozoa, which are destitute of a 

 mouth, and do not possess the power of emitting processes of their body- 

 substance (pseudopodia). 



CLASS B. RHIZOPODA. Protozoa, which are destitute of a mouth, and 

 have the power of emitting extensile and contractile processes of the body- 

 substance (pseudopodia). 



Order I. Monera. Ex. Protogenes. 

 Order 2. Amcebea. Ex. Amoeba. 

 Order 3. Foraminifera. Ex. Nummulites. 

 Order ^ Radiolaria. Ex. Haliomma. 

 Order 5. Spengida. Ex. Spongilla. 



CLASS C. INFUSORIA (Infusorian Animalcules). Protozoa mostly with 

 a mouth, and rudimentary digestive canal ; destitute of the power of emit- 

 ting pseudopodia; furnished with vibratile cilia or contractile filaments; 

 the body usually with a distinct cuticle covering a layer of firm sarcode. 



Regarded palaeontologically, we may eliminate from the Pro- 

 tozoa the entire class of the Gregarinidce, with the Rhizopodous 

 orders of the Monera and Amcebea, no trace of the past exis- 

 tence of which has yet been obtained, or, from their soft -bodied 

 nature, is ever likely to be. For all practical purposes the 

 same may be said of the large and universally-distributed class 

 of the Infusorian Animalcules. Some of these, however, possess 

 horny or membranous cases which might possibly be preserved 

 in a fossil state ; and it has been alleged that the genus Peri- 



